U.S. patent application number 14/570189 was filed with the patent office on 2016-06-16 for camshaft phaser with a rotary valve spool positioned hydraulically.
The applicant listed for this patent is DELPHI TECHNOLOGY INC.. Invention is credited to THOMAS H. FISCHER, KARL J. HALTINER, JR..
Application Number | 20160169060 14/570189 |
Document ID | / |
Family ID | 54849567 |
Filed Date | 2016-06-16 |
United States Patent
Application |
20160169060 |
Kind Code |
A1 |
FISCHER; THOMAS H. ; et
al. |
June 16, 2016 |
CAMSHAFT PHASER WITH A ROTARY VALVE SPOOL POSITIONED
HYDRAULICALLY
Abstract
A camshaft phaser includes an input member; an output member
defining a phasing advance chamber and a phasing retard chamber
with the input member; and a rotary valve spool coaxially disposed
within the output member such that the rotary valve spool is
rotatable relative to the output member and the input member, the
valve spool defining a rotary valve spool advance chamber and a
rotary valve spool retard chamber. Oil supplied to the rotary valve
spool advance chamber causes the rotary valve spool to rotate
relative to the output member and relative to the input member in a
retard direction and oil supplied to the rotary valve spool retard
chamber causes the rotary valve spool to rotate relative to the
output member and relative to the input member in an advance
direction.
Inventors: |
FISCHER; THOMAS H.;
(ROCHESTER, NY) ; HALTINER, JR.; KARL J.;
(FAIRPORT, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DELPHI TECHNOLOGY INC. |
Troy |
MI |
US |
|
|
Family ID: |
54849567 |
Appl. No.: |
14/570189 |
Filed: |
December 15, 2014 |
Current U.S.
Class: |
123/90.17 |
Current CPC
Class: |
F01L 1/047 20130101;
F01L 2001/3445 20130101; F01L 2001/34426 20130101; F01L 1/3442
20130101; F04C 2/344 20130101 |
International
Class: |
F01L 1/344 20060101
F01L001/344; F04C 2/344 20060101 F04C002/344; F01L 1/047 20060101
F01L001/047 |
Claims
1. A camshaft phaser for use with an internal combustion engine for
controllably varying the phase relationship between a crankshaft
and a camshaft in said internal combustion engine, said camshaft
phaser comprising: an input member connectable to said crankshaft
of said internal combustion engine to provide a fixed ratio of
rotation between said input member and said crankshaft; an output
member connectable to said camshaft of said internal combustion
engine and defining a phasing advance chamber and a phasing retard
chamber with said input member; and a rotary valve spool coaxially
disposed within said output member such that said rotary valve
spool is rotatable relative to said output member and said input
member, said rotary valve spool defining a rotary valve spool
advance chamber and a rotary valve spool retard chamber; wherein
oil supplied to said rotary valve spool advance chamber causes said
rotary valve spool to rotate relative to said output member and
relative to said input member in a retard direction; wherein oil
supplied to said rotary valve spool retard chamber causes said
rotary valve spool to rotate relative to said output member and
relative to said input member in an advance direction; wherein
rotation of said rotary valve spool in the advance direction allows
oil to be supplied to said phasing retard chamber, thereby causing
said output member to rotate relative to said input member in the
advance direction; and wherein rotation of said rotary valve spool
in the retard direction allows oil to be supplied to said phasing
advance chamber, thereby causing said output member to rotate
relative to said input member in the retard direction.
2. A camshaft phaser as in claim 1 further comprising a linear
valve spool displaceable axially such that said linear valve spool
controls oil flow to and from said rotary valve spool advance
chamber and said rotary valve spool retard chamber.
3. A camshaft phaser as in claim 1 further comprising a biasing
arrangement wherein: said biasing arrangement applies torque to
said rotary valve spool in the retard direction when said rotary
valve spool is advanced of a predetermined rotary valve spool
position relative to said input member; and said biasing
arrangement applies torque to said rotary valve spool in the
advance direction when said rotary valve spool is retarded of said
predetermined rotary valve spool position.
4. A camshaft phaser as in claim 3 further comprising a lock pin
which selectively prevents rotation between said output member and
said input member when said output member is in a predetermined
output member position relative to said input member which is
determined by said predetermined rotary valve spool position.
5. A camshaft phaser as in claim 1 wherein: said input member is a
stator having a plurality of lobes; said output member is a rotor
coaxially disposed within said stator, said rotor having a
plurality of vanes interspersed with said plurality of lobes; said
phasing advance chamber is one of a plurality of phasing advance
chambers defined by said plurality of vanes and said plurality of
lobes; and said phasing retard chamber is one of a plurality of
phasing retard chambers defined by said plurality of vanes and said
plurality of lobes.
6. A camshaft phaser as in claim 5 wherein: said rotary valve spool
advance chamber is one of a plurality of rotary valve spool advance
chambers defined by said rotary valve spool; and said rotary valve
spool retard chamber is one of a plurality of rotary valve spool
retard chambers defined by said rotary valve spool.
7. A camshaft phaser as in claim 6 wherein said rotary valve spool
is rotatably disposed within a rotor valve spool bore of said
rotor.
8. A camshaft phaser as in claim 7 wherein said plurality of rotary
valve spool advance chambers and said plurality of rotary valve
spool retard chambers are further defined by said rotor valve spool
bore.
9. A camshaft phaser as in claim 8 further comprising a plurality
of rotary valve spool vanes where each one of said plurality of
rotary valve spool vanes separates one of said plurality of rotary
valve spool advance chambers from one of said plurality of rotary
valve spool retard chambers.
10. A camshaft phaser as in claim 9 wherein each of said plurality
of rotary valve spool vanes is fixed to said rotor to prevent
relative rotation between said plurality of rotary valve spool
vanes and said rotor.
11. A camshaft phaser as in claim 10 wherein relative rotation
between said plurality of rotary valve spool vanes and said rotor
is prevented by each of said plurality of rotary valve spool vanes
having a rotary valve spool vane rib extending radially outward
therefrom which engages a respective complementary rotor notch
which extends radially outward from said rotor valve spool
bore.
12. A camshaft phaser as in claim 9 wherein said rotary valve spool
is rotatable relative to said plurality of rotary valve spool
vanes.
13. A camshaft phaser as in claim 6 further comprising a linear
valve spool displaceable axially such that said linear valve spool
controls oil flow to and from said plurality of rotary valve spool
advance chambers and said plurality of rotary valve spool retard
chambers.
14. A camshaft phaser as in claim 13 wherein said linear valve
spool is axially displaceable between an advance position and a
retard position wherein: said advance position allows oil to flow
into said plurality of rotary valve spool retard chambers from an
oil source and allows oil to be vented from said plurality of
rotary valve spool advance chambers; and said retard position
allows oil to flow into said plurality of rotary valve spool
advance chambers from said oil source and allows oil to be vented
from said plurality of rotary valve spool retard chambers.
15. A camshaft phaser as in claim 14 wherein said linear valve
spool is axially displaceable between a default position in
addition to said advance position and said retard position wherein
said default position places said plurality of rotary valve spool
advance chambers in fluid communication with said plurality of
rotary valve spool retard chambers.
16. A camshaft phaser as in claim 15 further comprising a biasing
arrangement wherein: said biasing arrangement applies torque to
said rotary valve spool in the retard direction when said rotary
valve spool is advanced of a predetermined rotary valve spool
position relative to said stator, thereby rotating said rotary
valve spool relative to said rotor and said stator when said linear
valve spool is in said default position in order to position said
rotary valve spool in said predetermined rotary valve spool
position by allowing oil to flow from said plurality of rotary
valve spool retard chambers to said plurality of rotary valve spool
advance chambers; and said biasing arrangement applies torque to
said rotary valve spool in the advance direction when said rotary
valve spool is retarded of said predetermined rotary valve spool
position, thereby rotating said rotary valve spool relative to said
rotor and said stator when said linear valve spool is in said
default position in order to position said rotary valve spool in
said predetermined rotary valve spool position by allowing oil to
flow from said plurality of rotary valve spool advance chambers to
said plurality of rotary valve spool retard chambers.
17. A camshaft phaser as in claim 16 wherein said biasing
arrangement comprises: an advance bias spring which applies torque
to said rotary valve spool in the advance direction when said
rotary valve spool is retarded of said predetermined rotary valve
spool position; and a retard bias spring which applies torque to
said rotary valve spool in the retard direction when said rotary
valve spool is advanced of said predetermined rotary valve spool
position relative to said stator.
18. A camshaft phaser as in claim 17 further comprising: a back
cover closing one axial end of said stator; a front cover closing
the other axial end of said stator such that said plurality of
phasing advance chambers and said plurality of phasing retard
chambers are defined axially between said back cover and said front
cover, said front cover having a front cover central bore extending
coaxially therethrough; wherein said rotary valve spool is
rotatably disposed within a rotor valve spool bore of said rotor;
and wherein said rotary valve spool is captured axially between
said rotor valve spool bore and said front cover.
19. A camshaft phaser as in claim 18 wherein said rotary valve
spool includes a bias spring extension which extends through said
front cover central bore such that said advance bias spring engages
said bias spring extension when said rotary valve spool is retarded
of the predetermined rotary valve spool position and such that said
retard bias spring engages said bias spring extension when said
rotary valve spool is advanced of the predetermined rotary valve
spool position.
20. A camshaft phaser as in claim 14 wherein said linear valve
spool is axially displaceable between a hold position in addition
to said advance position and said retard position wherein said hold
position prevents oil from entering and exiting said plurality of
rotary valve spool advance chambers and said plurality of rotary
valve spool retard chambers, thereby preventing said rotary valve
spool from rotating relative to said rotor.
21. A camshaft phaser as in claim 6 further comprising a biasing
arrangement wherein: said biasing arrangement applies torque to
said rotary valve spool in the retard direction when said rotary
valve spool is advanced of a predetermined rotary valve spool
position relative to said stator; and said biasing arrangement
applies torque to said rotary valve spool in the advance direction
when said rotary valve spool is retarded of said predetermined
rotary valve spool position.
22. A camshaft phaser as in claim 21 further comprising a lock pin
which selectively prevents rotation between said rotor and said
stator when said rotor is in a predetermined rotor position
relative to said stator which is determined by said predetermined
rotary valve spool position.
23. A camshaft phaser as in claim 21 wherein said biasing
arrangement comprises: an advance bias spring which applies torque
to said rotary valve spool in the advance direction when said
rotary valve spool is retarded of said predetermined rotary valve
spool position; and a retard bias spring which applies torque to
said rotary valve spool in the retard direction when said rotary
valve spool is advanced of a predetermined rotary valve spool
position relative to said stator.
24. A camshaft phaser as in claim 23 wherein: one end of said
advance bias spring is grounded to said stator and the other end of
said advance bias spring engages said rotary valve spool only when
said rotary valve spool is retarded of said predetermined rotary
valve spool position; and one end of said retard bias spring is
grounded to said stator and the other end of said retard bias
spring engages said rotary valve spool only when said rotary valve
spool is advanced of said predetermined rotary valve spool
position.
25. A camshaft phaser for use with an internal combustion engine
for controllably varying the phase relationship between a
crankshaft and a camshaft in said internal combustion engine, said
camshaft phaser comprising: an input member connectable to said
crankshaft of said internal combustion engine to provide a fixed
ratio of rotation between said input member and said crankshaft; an
output member connectable to said camshaft of said internal
combustion engine and defining a phasing advance chamber and a
phasing retard chamber with said input member; a rotary valve spool
coaxially disposed within said output member such that said rotary
valve spool is rotatable relative to said output member and said
input member; and a biasing arrangement which applies torque to
said rotary valve spool toward a predetermined rotary valve spool
position relative to said input member; wherein rotation of said
rotary valve spool in an advance direction allows oil to be
supplied to said phasing retard chamber, thereby causing said
output member to rotate relative to said input member in the
advance direction; and wherein rotation of said rotary valve spool
in a retard direction allows oil to be supplied to said phasing
advance chamber, thereby causing said output member to rotate
relative to said input member in the retard direction.
26. A camshaft phaser as in claim 25 wherein: said biasing
arrangement applies torque to said rotary valve spool in the retard
direction when said rotary valve spool is advanced of the
predetermined rotary valve spool position; and said biasing
arrangement applies torque to said rotary valve spool in the
advance direction when said rotary valve spool is retarded of said
predetermined rotary valve spool position.
27. A camshaft phaser as in claim 26 wherein said biasing
arrangement comprises: an advance bias spring which applies torque
to said rotary valve spool in the advance direction when said
rotary valve spool is retarded of said predetermined rotary valve
spool position; and a retard biasing spring which applies torque to
said rotary valve spool in the retard direction when said rotary
valve spool is advanced of said predetermined rotary valve spool
position.
Description
TECHNICAL FIELD OF INVENTION
[0001] The present invention relates to a camshaft phaser for
varying the phase relationship between a crankshaft and a camshaft
in an internal combustion engine; more particularly to such a
camshaft phaser which is a vane-type camshaft phaser; even more
particularly to a vane-type camshaft phaser which includes a rotary
valve spool in which the position of the rotary valve spool
determines the phase relationship between the crankshaft and the
camshaft; and still even more particularly to such a camshaft
phaser which uses hydraulics to position the rotary valve spool,
and still yet even more particularly to such a camshaft phaser
which includes a linear valve spool to control oil flow for
positioning the rotary valve spool.
BACKGROUND OF INVENTION
[0002] Camshaft phasers are known for changing the phase
relationship between a crankshaft and a camshaft in an internal
combustion engine in order to achieve desired engine performance.
U.S. Pat. No. 5,507,254 to Melchior, hereinafter referred to as
Melchior, teaches a camshaft phaser comprising a rotor with an
outward extending vane and a stator with an inward extending lobe
such that the rotor is located within the stator and the vane and
lobe together define and advance chamber and a retard chamber. Oil
is selectively supplied to either the advance chamber or the retard
chamber and vacated from the other of the advance chamber and
retard chamber as directed by a phasing oil control valve in order
to rotate the rotor within the stator and thereby change the phase
relationship between the camshaft and the crankshaft. It is also
known in the camshaft phaser art to provide the rotor with a
plurality of vanes and to provide the stator with a plurality of
lobes, thereby defining a plurality of alternating advance chambers
and retard chambers. Melchior also teaches that the phasing oil
control valve that may be rotated in order to supply and vacate oil
from the advance chamber and the retard chamber. The phasing oil
control valve is directly and mechanically rotated by an arm that
is sensitive to engine speed such that the rotational position of
the phasing oil control valve determines the rotational position of
the rotor relative to the stator. The valve spool defines a first
recess and a second recess separated by a rib such that one of the
recesses acts to supply oil to the advance chamber when a retard in
timing of the camshaft is desired while the other recess acts to
supply oil to the retard chamber when an advance in the timing of
the camshaft is desired. The recess that does not act to supply oil
when a change in phase is desired does not act as a flow path.
Rotating the phasing oil control valve directly and mechanically by
an arm that is sensitive to engine speed may not be adequate for
operation because modern internal combustion engines rely on many
parameters, typically provided by various sensors which monitor
various aspects of engine performance, processed by an electronic
processor, for example an engine control module, to determine a
desired camshaft phase. Consequently, it is desirable to
rotationally position the phasing oil control valve taking into
account any number of engine performance indicators.
[0003] What is needed is a camshaft phaser which minimizes or
eliminates one or more of the shortcomings as set forth above.
SUMMARY OF THE INVENTION
[0004] Briefly described, a camshaft phaser is provided for use
with an internal combustion engine for controllably varying the
phase relationship between a crankshaft and a camshaft in the
internal combustion engine where the camshaft phaser includes an
input member which is connectable to the crankshaft of the internal
combustion engine to provide a fixed ratio of rotation between the
input member and the crankshaft; an output member which is
connectable to the camshaft of the internal combustion engine and
defining a phasing advance chamber and a phasing retard chamber
with the input member; and a rotary valve spool coaxially disposed
within the output member such that the rotary valve spool is
rotatable relative to the output member and the input member, the
valve spool defining a rotary valve spool advance chamber and a
rotary valve spool retard chamber. Oil supplied to the rotary valve
spool advance chamber causes the rotary valve spool to rotate
relative to the output member and relative to the input member in a
retard direction; oil supplied to the rotary valve spool retard
chamber causes the rotary valve spool to rotate relative to the
output member and relative to the input member in an advance
direction; rotation of the rotary valve spool in the advance
direction allows oil to be supplied to the retard chamber, thereby
causing the output member to rotate relative to the input member in
the advance direction; and rotation of the rotary valve spool in
the retard direction allows oil to be supplied to the advance
chamber, thereby causing the output member to rotate relative to
the input member in the retard direction.
[0005] A camshaft phaser is also provided for use with an internal
combustion engine for controllably varying the phase relationship
between a crankshaft and a camshaft in the internal combustion
engine where the camshaft phaser includes an input member
connectable to the crankshaft of the internal combustion engine to
provide a fixed ratio of rotation between the input member and the
crankshaft; an output member connectable to the camshaft of the
internal combustion engine and defining a phasing advance chamber
and a phasing retard chamber with the input member; a rotary valve
spool coaxially disposed within the output member such that the
rotary valve spool is rotatable relative to the output member and
the input member; and a biasing arrangement which applies torque to
the rotary valve spool toward a predetermined rotary valve spool
position relative to the input member. Rotation of the rotary valve
spool in the advance direction allows oil to be supplied to the
retard chamber, thereby causing the output member to rotate
relative to the input member in the advance direction; and rotation
of the rotary valve spool in the retard direction allows oil to be
supplied to the advance chamber, thereby causing the output member
to rotate relative to the input member in the retard direction.
[0006] Further features and advantages of the invention will appear
more clearly on a reading of the following detailed description of
the preferred embodiment of the invention, which is given by way of
non-limiting example only and with reference to the accompanying
drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0007] This invention will be further described with reference to
the accompanying drawings in which:
[0008] FIG. 1 is an exploded isometric view of a camshaft phaser in
accordance with the present invention;
[0009] FIG. 2 is an exploded isometric view of a rotary valve spool
of the camshaft phaser in accordance with the present
invention;
[0010] FIG. 3 is an axial cross-sectional view of the camshaft
phaser of FIG. 1;
[0011] FIG. 4 is a radial cross-sectional view of the camshaft
phaser of FIG. 1 taken through section line 4-4 of FIG. 3;
[0012] FIG. 5 is a radial cross-sectional view of the camshaft
phaser of FIG. 1 taken through section line 5-5 of FIG. 3;
[0013] FIG. 6 is an axial cross-sectional view of a portion of the
camshaft phaser of FIG. 1 with a linear valve spool of the camshaft
phaser in a default position;
[0014] FIG. 7A is the axial cross-sectional view of FIG. 6 now with
the linear valve spool shown in a retard position;
[0015] FIG. 7B is the radial cross-sectional view of FIG. 4 showing
the rotary valve spool after being rotated as a result of the
linear valve spool position of FIG. 7A;
[0016] FIG. 7C is the radial cross-sectional view of FIG. 5 showing
the rotary valve spool after being rotated as a result of the
linear valve spool position of FIG. 7A;
[0017] FIG. 7D is the radial cross-sectional view of FIG. 7C
showing the rotor after being rotated as a result of the position
of the rotary valve spool as shown in FIG. 7C;
[0018] FIG. 7E is the radial cross-sectional view of FIG. 7C with
reference numbers removed in order to clearly shown the path of oil
flow as a result of the position of the rotary valve spool as shown
in FIG. 7C;
[0019] FIG. 8 is the an axial cross-sectional view of FIG. 6 with
the linear valve spool of the camshaft phaser in a hold
position;
[0020] FIG. 9A is the axial cross-sectional view of FIG. 6 now with
the linear valve spool shown in an advance position;
[0021] FIG. 9B is the radial cross-sectional view of FIG. 4 showing
the rotary valve spool after being rotated as a result of the
linear valve spool position of FIG. 9A;
[0022] FIG. 9C is the radial cross-sectional view of FIG. 5 showing
the rotary valve spool after being rotated as a result of the
linear valve spool position of FIG. 9A;
[0023] FIG. 9D is the radial cross-sectional view of FIG. 9C
showing the rotor after being rotated as a result of the position
of the rotary valve spool as shown in FIG. 9C; and
[0024] FIG. 9E is the radial cross-sectional view of FIG. 9C with
reference numbers removed in order to clearly shown the path of oil
flow as a result of the position of the rotary valve spool as shown
in FIG. 9C.
DETAILED DESCRIPTION OF INVENTION
[0025] In accordance with a preferred embodiment of this invention
and referring to FIGS. 1-5, an internal combustion engine 10 is
shown which includes a camshaft phaser 12. Internal combustion
engine 10 also includes a camshaft 14 which is rotatable about a
camshaft axis 16 based on rotational input from a crankshaft and
chain (not shown) driven by a plurality of reciprocating pistons
(also not shown). As camshaft 14 is rotated, it imparts valve
lifting and closing motion to intake and/or exhaust valves (not
shown) as is well known in the internal combustion engine art.
Camshaft phaser 12 allows the timing or phase between the
crankshaft and camshaft 14 to be varied. In this way, opening and
closing of the intake and/or exhaust valves can be advanced or
retarded in order to achieve desired engine performance.
[0026] Camshaft phaser 12 generally includes a stator 18 which acts
as an input member, a rotor 20 disposed coaxially within stator 18
which acts as an output member, a back cover 22 closing off one
axial end of stator 18, a front cover 24 closing off the other
axial end of stator 18, a camshaft phaser attachment bolt 26 for
attaching camshaft phaser 12 to camshaft 14, a rotary valve spool
28 used to direct oil for rotating rotor 20 relative to stator 18,
a linear valve spool 30 used to supply oil to rotary valve spool 28
for rotationally positioning rotary valve spool 28 relative to
stator 18, a lock pin 31 for selectively preventing relative
rotation between rotor 20 and stator 18, and a biasing arrangement
32 for biasing rotary valve spool 28 to a predetermined rotary
valve spool position of rotary valve spool 28 relative to stator
18. The rotational position of rotary valve spool 28 relative to
stator 18 determines the rotational position of rotor 20 relative
to stator 18, unlike typical valve spools which move axially to
determine only the direction the rotor will rotate relative to the
stator. The various elements of camshaft phaser 12 will be
described in greater detail in the paragraphs that follow.
[0027] Stator 18 is generally cylindrical and includes a plurality
of radial chambers 34 defined by a plurality of lobes 36 extending
radially inward. In the embodiment shown, there are three lobes 36
defining three radial chambers 34, however, it is to be understood
that a different number of lobes 36 may be provided to define
radial chambers 34 equal in quantity to the number of lobes 36.
[0028] Rotor 20 includes a rotor central hub 38 with a plurality of
vanes 40 extending radially outward therefrom, a rotor central
through bore 42 extending axially therethrough, and a stepped rotor
valve spool recess 44 coaxial with rotor central through bore 42
and extending part way into rotor 20 from the axial end of rotor 20
that is distal from camshaft 14. The number of vanes 40 is equal to
the number of radial chambers 34 provided in stator 18. Rotor 20 is
coaxially disposed within stator 18 such that each vane 40 divides
each radial chamber 34 into phasing advance chambers 46 and phasing
retard chambers 48. The radial tips of lobes 36 are mateable with
rotor central hub 38 in order to separate radial chambers 34 from
each other. While not shown, each of the radial tips of vanes 40
may include a wiper seal to substantially seal adjacent phasing
advance chambers 46 and phasing retard chambers 48 from each other
as shown in United States Patent Application Publication No. US
2014/0123920 A1 to Lichti et al., the disclosure of which is
incorporated herein by reference in its entirety. Similarly, each
of the radial tips of lobes 36 may also include a wiper seal to
substantially seal adjacent phasing advance chambers 46 and phasing
retard chambers 48 from each other.
[0029] Rotor valve spool recess 44 is defined by an outer rotor
valve spool recess bore 50 and an inner rotor valve spool recess
bore 52 axially adjacent to outer rotor valve spool recess bore 50
such that outer rotor valve spool recess bore 50 is larger in
diameter than inner rotor valve spool recess bore 52 and such that
inner rotor valve spool recess bore 52 is axially between outer
rotor valve spool recess bore 50 and rotor central through bore 42.
An outer valve spool recess shoulder 54 is defined by the surface
of rotor valve spool recess 44 which connects inner rotor valve
spool recess bore 52 to outer rotor valve spool recess bore 50 such
that outer valve spool recess shoulder 54 is annular in shape and
substantially perpendicular to camshaft axis 16. Inner rotor valve
spool recess bore 52 is larger in diameter than rotor central
through bore 42, and consequently, an inner valve spool recess
shoulder 56 is defined by the surface of rotor valve spool recess
bore 44 which connects rotor central through bore 42 to inner rotor
valve spool recess bore 52 such that inner valve spool recess
shoulder 56 is annular in shape and substantially perpendicular to
camshaft axis 16.
[0030] Back cover 22 is sealingly secured, using cover bolts 58, to
the axial end of stator 18 that is proximal to camshaft 14.
Tightening of cover bolts 58 prevents relative rotation between
back cover 22 and stator 18. Back cover 22 includes a back cover
central bore 60 extending coaxially therethrough. The end of
camshaft 14 is received coaxially within back cover central bore 60
such that camshaft 14 is allowed to rotate relative to back cover
22. Back cover 22 may also include a lock pin seat 62 which
selectively receives lock pin 31 as will be described in greater
detail later. Back cover 22 may also include a sprocket 64 formed
integrally therewith or otherwise fixed thereto. Sprocket 64 is
configured to be driven by a chain that is driven by the crankshaft
of internal combustion engine 10. Alternatively, sprocket 64 may be
a pulley driven by a belt or any other known drive member for
driving camshaft phaser 12 by the crankshaft. In an alternative
arrangement, sprocket 64 may be integrally formed or otherwise
attached to stator 18 rather than back cover 22.
[0031] Similarly, front cover 24 is sealingly secured, using cover
bolts 58, to the axial end of stator 18 that is opposite back cover
22. Cover bolts 58 pass through back cover 22 and stator 18 and
threadably engage front cover 24; thereby clamping stator 18
between back cover 22 and front cover 24 to prevent relative
rotation between stator 18, back cover 22, and front cover 24. In
this way, phasing advance chambers 46 and phasing retard chambers
48 are defined axially between back cover 22 and front cover 24.
Front cover 24 includes a front cover central bore 66 extending
coaxially therethrough.
[0032] Camshaft phaser 12 is attached to camshaft 14 with camshaft
phaser attachment bolt 26 which extends coaxially through rotor
central through bore 42 of rotor 20 and threadably engages camshaft
14, thereby by clamping rotor 20 securely to camshaft 14. More
specifically, camshaft phaser attachment bolt 26 includes a
camshaft phaser attachment bolt shoulder 68 which is substantially
perpendicular to camshaft axis 16 and which mates with inner valve
spool recess shoulder 56 of rotor 20. Consequently, rotor 20 is
clamped between camshaft phaser attachment bolt shoulder 68 and
camshaft 14. In this way, relative rotation between stator 18 and
rotor 20 results in a change in phase or timing between the
crankshaft of internal combustion engine 10 and camshaft 14.
[0033] Oil is selectively transferred to phasing advance chambers
46 from phasing retard chambers 48, as result of torque applied to
camshaft 14 from the valve train of internal combustion engine 10,
i.e. torque reversals of camshaft 14, in order to cause relative
rotation between stator 18 and rotor 20 which results in retarding
the timing of camshaft 14 relative to the crankshaft of internal
combustion engine 10. Conversely, oil is selectively transferred to
phasing retard chambers 48 from phasing advance chambers 46, as
result of torque applied to camshaft 14 from the valve train of
internal combustion engine 10, in order to cause relative rotation
between stator 18 and rotor 20 which results in advancing the
timing of camshaft 14 relative to the crankshaft of internal
combustion engine 10. Rotor advance passages 70 may be provided in
rotor 20 for supplying and venting oil to and from phasing advance
chambers 46 while rotor retard passages 72 may be provided in rotor
20 for supplying and venting oil to and from phasing retard
chambers 48. Rotor advance passages 70 extend radially outward
through rotor central hub 38 from outer rotor valve spool recess
bore 50 to phasing advance chambers 46 while rotor retard passages
72 extend radially outward through rotor central hub 38 from outer
rotor valve spool recess bore 50 to phasing retard chambers 48.
Transferring oil to phasing advance chambers 46 from phasing retard
chambers 48 and transferring oil to phasing retard chambers 48 from
phasing advance chambers 46 is controlled by rotary valve spool 28,
recirculation check valves 74, and linear valve spool 30 as will be
described in detail later, such that rotary valve spool 28 is
disposed coaxially and rotatably within stepped rotor valve spool
recess 44.
[0034] Rotor 20 and rotary valve spool 28, which act together to
function as a valve to rotate rotor 20 relative to stator 18, will
now be described in greater detail with continued reference to
FIGS. 1-5. Rotary valve spool 28 includes a rotary valve body 76, a
rotary valve spool biasing body 78, and rotary valve spool vanes
80.
[0035] Rotary valve body 76 is defined by a rotary valve body outer
portion 82 located within outer rotor valve spool recess bore 50
and a rotary valve body inner portion 84 located within inner rotor
valve spool recess bore 52 such that a rotary valve body through
bore 86 is centered about camshaft axis 16 and extends coaxially
through rotary valve body outer portion 82 and rotary valve body
inner portion 84. Camshaft phaser attachment bolt 26 extends
coaxially through rotary valve body through bore 86 in a close
sliding interface such that rotary valve body 76 is able to rotate
freely relative to camshaft phaser attachment bolt 26 while
substantially preventing oil from passing between the interface of
camshaft phaser attachment bolt 26 and rotary valve body through
bore 86. Rotary valve body inner portion 84 is coaxially located
within inner rotor valve spool recess bore 52 and is sized to mate
radially with inner rotor valve spool recess bore 52 in a close
sliding interface such that rotary valve body inner portion 84 is
able to freely rotate within inner rotor valve spool recess bore 52
while substantially preventing oil from passing between the
interface of rotary valve body inner portion 84 and inner rotor
valve spool recess bore 52. A plurality of rotary valve body
phasing chambers 88 extend radially into rotary valve body inner
portion 84 from the outer circumference thereof such that rotary
valve body phasing chambers 88 are arranged in a polar array where
adjacent rotary valve body phasing chambers 88 are sealingly
separated from each other by one of a plurality of rotary valve
body phasing chamber walls 90 and such that rotary valve body
phasing chambers 88 are formed in the shape of a segment of an
annulus. In the embodiment shown, there are three rotary valve body
phasing chambers 88, however, any number of rotary valve body
phasing chambers 88 may be provided. Rotary valve body phasing
chambers 88 are delimited axially at one end by a rotary valve body
inner portion end wall 92 which defines an axial end of rotary
valve body inner portion 84 that is proximal to inner valve spool
recess shoulder 56 and rotary valve body phasing chambers 88 are
delimited axially at the other end by rotary valve body outer
portion 82. Rotary valve body phasing chambers 88 are delimited
radially inward by a rotary valve body inner portion inner wall 94
and are delimited radially outward by inner rotor valve spool
recess bore 52.
[0036] Each rotary valve spool vane 80 is received within a
respective rotary valve body phasing chamber 88, thereby dividing
each rotary valve body phasing chamber 88 into a rotary valve spool
advance chamber 96 and a rotary valve spool retard chamber 98. Each
rotary valve spool vane 80 is formed in the shape of a segment of
an annulus which mates radially inward with rotary valve body inner
portion inner wall 94 and radially outward with inner rotor valve
spool recess bore 52 in close sliding interfaces such that rotary
valve body 76 is able to rotate relative to rotary valve spool
vanes 80 while substantially preventing oil from passing between
the interface formed between rotary valve spool vanes 80 and rotary
valve body inner portion inner wall 94 and the interfaces formed
between rotary valve spool vanes 80 and inner rotor valve spool
recess bore 52. Rotary valve spool vanes 80 are sized to mate
axially with rotary valve body inner portion end wall 92 and
axially with rotary valve body outer portion 82 in close sliding
interfaces such that, that rotary valve body 76 is able to rotate
relative to rotary valve spool vanes 80 while substantially
preventing oil from passing between the interface formed between
rotary valve spool vanes 80 and rotary valve body inner portion end
wall 92 and the interfaces formed between rotary valve spool vanes
80 and rotary valve body outer portion 82. In this way, rotary
valve spool advance chambers 96 and rotary valve spool retard
chambers 98 are fluidly isolated from each other. It should be
noted that each rotary valve spool vane 80 has an angular length
that is less than the angular length of each rotary valve body
phasing chamber 88, thereby allowing rotary valve body 76 to rotate
relative to rotor 20. Each rotary valve spool vane 80 is fixed to
rotor 20 in order to prevent relative movement between rotary valve
spool vanes 80 and rotor 20. As shown, each rotary valve spool vane
80 may be fixed to rotor 20 by a rotary valve spool vane rib 100
which extends radially outward therefrom and engages a
complementary rotor notch 102 which extends radially outward from
inner rotor valve spool recess bore 52. During assembly of camshaft
phaser 12, rotary valve spool vanes 80 are first assembled into
respective rotary valve body phasing chambers 88, then rotary valve
spool 28 is inserted into rotor valve spool recess 44, thereby
engaging rotary valve spool vane ribs 100 with rotor notches
102.
[0037] Oil is selectively supplied to rotary valve spool retard
chambers 98 and vented from rotary valve spool advance chambers 96
in order to rotate rotary valve spool 28 in the advance direction
of rotation. Conversely, oil is selectively supplied to rotary
valve spool advance chambers 96 and vented from rotary valve spool
retard chambers 98 in order to rotate rotary valve spool 28 in the
retard direction of rotation. For clarity, FIGS. 4, 5, 7B-7E, and
9B-9E include arrows indicating the directions of advance and
retard because in FIGS. 4, 7C-7E and 9C-9E advance is clockwise and
retard is counterclockwise due to the direction of viewing camshaft
phaser 12 while in FIGS. 5, 7B, and 9B advance is counterclockwise
and retard is clockwise due to the direction of viewing camshaft
phaser 12. Rotary valve spool advance passages 104 may be provided
in rotary valve body 76 for supplying and venting oil to and from
rotary valve spool advance chambers 96 while rotary valve spool
retard passages 106 may be provided in rotary valve body 76 for
supplying and venting oil to and from rotary valve spool retard
chambers 98. Rotary valve spool advance passages 104 extend from
respective rotary valve spool advance chambers 96 through rotary
valve body 76 to a rotary valve body annular advance groove 108
which is formed in rotary valve body 76 such that rotary valve body
annular advance groove 108 extends radially outward from rotary
valve body through bore 86. Similarly, rotary valve spool retard
passages 106 extend from respective rotary valve spool retard
chambers 98 through rotary valve body 76 to a rotary valve body
annular retard groove 110 which is formed in rotary valve body 76
such that rotary valve body annular retard groove 110 extends
radially outward from rotary valve body through bore 86. Rotary
valve body annular retard groove 110 is axially spaced from rotary
valve body annular advance groove 108 such that rotary valve body
annular retard groove 110 is proximal to camshaft 14 and rotary
valve body annular advance groove 108 is distal from camshaft
14.
[0038] Rotary valve body outer portion 82 is coaxially located
within outer rotor valve spool recess bore 50 and is sized to mate
radially with outer rotor valve spool recess bore 50 in a close
sliding interface such that rotary valve body outer portion 82 is
able to freely rotate within outer rotor valve spool recess bore 50
while substantially preventing oil from passing between the
interface of rotary valve body outer portion 82 and outer rotor
valve spool recess bore 50. A plurality of supply chambers 112 and
a plurality of vent chambers 114 are formed in the outer
circumference of rotary valve body outer portion 82 such that
adjacent supply chambers 112 and vent chambers 114 are separated by
respective rotary valve spool lands 116 which are sized to be about
the same width as rotor advance passages 70 and rotor retard
passages 72. Each supply chamber 112 and each vent chamber 114
extends axially part way along the length of rotary valve spool
biasing body 78 from the axial end of rotary valve body outer
portion 82 that mates with rotary valve spool biasing body 78. An
annular rotary valve spool recirculation groove 118 is formed in
the axial end rotary valve body outer portion 82 that mates with
rotary valve spool biasing body 78. Fluid communication between
annular rotary valve spool recirculation groove 118 and supply
chambers 112 is provided by a plurality of recirculation recesses
120 formed in the axial face of rotary valve body outer portion 82
that mates with rotary valve spool biasing body 78. Fluid
communication between annular rotary valve spool recirculation
groove 118 and vent chambers 114 is provided by a plurality of
rotary valve spool recirculation passages 122 formed in rotary
valve body outer portion 82 such that each rotary valve spool
recirculation passage 122 extends radially inward from a respective
vent chambers 114, then axially to annular rotary valve spool
recirculation groove 118. Recirculation check valves 74 allow oil
to flow from vent chambers 114 to supply chambers 112 while
preventing oil from flowing from supply chambers 112 to vent
chambers 114 as will be described in greater detail later. Each
recirculation check valve 74 may be integrally formed as part of a
recirculation check valve plate 126 which is annular in shape and
sized to fit within annular rotary valve spool recirculation groove
118 such that the thickness of recirculation check valve plate 126
is less than the depth of annular rotary valve spool recirculation
groove 118. Each recirculation check valve 74 may be located at the
end of a recirculation check valve arm 128 which is defined by a
recirculation check valve slot 130 formed through recirculation
check valve plate 126. In this way, each recirculation check valve
74 acts as a reed valve and can be easily and economically formed,
by way of non-limiting example only, by stamping sheet metal stock.
Recirculation check valve plate 126 may be radially indexed and
retained within annular rotary valve spool recirculation groove 118
by recirculation check valve plate screws 132 which extend through
recirculation check valve plate 126 and threadably engage rotary
valve body outer portion 82. An annular rotary valve body lock pin
groove 134 is formed on the outer circumference of rotary valve
body outer portion 82 such that annular rotary valve body lock pin
groove 134 is axially between supply chambers 112 and rotary valve
body inner portion 84 and such that annular rotary valve body lock
pin groove 134 is aligned with a rotor lock pin passage 136 in
rotor 20 which is used to supply and vent oil to and from lock pin
31 as will be described in greater detail later. A rotary valve
spool lock pin passage 137 extends from annular rotary valve body
lock pin groove 134 to the inner circumference of rotary valve body
through bore 86 for supplying and venting oil to and from annular
rotary valve body lock pin groove 134 as will also be described in
greater detail later.
[0039] Rotary valve spool biasing body 78 includes a rotary valve
spool biasing body base 138 located axially between rotary valve
body outer portion 82 and front cover 24 and also includes a bias
spring extension 140 which extends axially away from rotary valve
spool biasing body base 138 and through front cover central bore
66. Rotary valve spool biasing body base 138 is annular in shape
and sized to mate radially with outer rotor valve spool recess bore
50 in a close sliding interface such that rotary valve spool
biasing body base 138 is able to freely rotate within outer rotor
valve spool recess bore 50 while substantially preventing oil from
passing between the interface of rotary valve spool biasing body
base 138 and outer rotor valve spool recess bore 50. Rotary valve
spool biasing body base 138 includes a rotary valve spool biasing
body central through bore 142 which extends axially therethrough
such that rotary valve spool biasing body base 138 is centered
about camshaft axis 16. Rotary valve spool biasing body central
through bore 142 is sized to mate radially with camshaft phaser
attachment bolt 26 in a close sliding interface such that rotary
valve spool biasing body base 138 is able to freely rotate relative
to camshaft phaser attachment bolt 26 while substantially
preventing oil from passing between the interface of rotary valve
spool biasing body central through bore 142 and camshaft phaser
attachment bolt 26. Rotary valve spool biasing body base 138 is
sealingly secured to rotary valve body outer portion 82 with rotary
valve spool biasing body screws 144 which extend through rotary
valve spool biasing body base 138 and threadably engage rotary
valve body outer portion 82, thereby substantially preventing oil
from passing between the interface of rotary valve spool biasing
body base 138 and rotary valve body outer portion 82. Bias spring
extension 140 is arc shaped, thereby defining a first bias spring
extension end 146 for engaging one end of an advance bias spring
148 as will be discussed in greater detail later and also defining
a second bias spring extension end 150 for engaging one end of a
retard bias spring 152 as will also be discussed in greater detail
later.
[0040] Linear valve spool 30 and camshaft phaser attachment bolt
26, which act together to function as a valve to rotate rotary
valve spool 28 relative to stator 18 and rotor 20, will now be
described in greater detail with continued reference to FIGS. 1-5
and now with additional reference to FIG. 6. Linear valve spool 30
is located within a valve bore 154 of camshaft phaser attachment
bolt 26 such that valve bore 154 is centered about camshaft axis 16
and such that linear valve spool 30 is moved axially within valve
bore 154 by an actuator 156 and a valve spring 158.
[0041] Linear valve spool 30 is sized to mate radially with valve
bore 154 in a close sliding interface such that linear valve spool
30 is able to freely slide axially within valve bore 154 while
substantially preventing oil from passing between the interface of
linear valve spool 30 and valve bore 154. A linear valve spool
spring seat 160 is formed at one axial end of linear valve spool 30
for receiving one end of valve spring 158, thereby capturing valve
spring 158 axially between linear valve spool 30 and the bottom of
valve bore 154. Three grooves extend radially into linear valve
spool 30 where a linear valve spool supply groove 162 extends
radially into linear valve spool 30 near the end of linear valve
spool 30 which defines linear valve spool spring seat 160, a linear
valve spool lock pin supply groove 164 extends radially into linear
valve spool 30 near the end of linear valve spool 30 that is distal
from linear valve spool spring seat 160, and a linear valve spool
advance supply groove 165 extends radially into linear valve spool
30 at a location axially between linear valve spool supply groove
162 and linear valve spool lock pin supply groove 164.
Consequently, linear valve spool supply groove 162, linear valve
spool lock pin supply groove 164, and linear valve spool advance
supply groove 165 define four lands on linear valve spool 30 where
a linear valve spool supply land 166 is located at the end of
linear valve spool 30 that is proximal to the bottom of valve bore
154, a linear valve spool vent land 168 is located at the end of
linear valve spool 30 that is opposite linear valve spool supply
land 166, a linear valve spool retard land 169 is located between
linear valve spool supply land 166 and linear valve spool vent land
168 such that linear valve spool retard land 169 is proximal to
linear valve spool supply land 166, and a linear valve spool
advance land 170 is located between linear valve spool supply land
166 and linear valve spool retard land 169. A linear valve spool
axial vent passage 172 extends axially into linear valve spool 30
from linear valve spool spring seat 160 such that linear valve
spool axial vent passage 172 is centered about camshaft axis 16. A
pair of linear valve spool axial supply passages 174 extend axially
within linear valve spool 30 from linear valve spool supply groove
162 such that each linear valve spool axial supply passage 174 is
radially offset from linear valve spool axial vent passage 172 and
substantially parallel to linear valve spool axial vent passage
172. In order to facilitate formation of linear valve spool axial
vent passage 172, each linear valve spool axial vent passage 172
may begin at linear valve spool vent land 168 and a plug 176 is
placed in the end of each linear valve spool axial supply passage
174 that is proximal to linear valve spool vent land 168 in order
to terminate each linear valve spool axial supply passages 174.
Linear valve spool axial vent passage 172 includes a first linear
valve spool radial vent passage 178 extending radially outward
therefrom and through linear valve spool retard land 169 to the
outer circumference of linear valve spool retard land 169 and a
second linear valve spool radial vent passage 180 extending
radially outward therefrom and through linear valve spool advance
land 170 to the outer circumference of linear valve spool advance
land 170. Each linear valve spool axial supply passages 174
includes a linear valve spool retard supply passage 182 extending
radially outward therefrom and through linear valve spool retard
land 169 to the outer circumference of linear valve spool retard
land 169, a linear valve spool advance supply passage 184 extending
radially outward therefrom to linear valve spool advance supply
groove 165, and a linear valve spool lock pin supply passage 186
extending radially outward therefrom to linear valve spool lock pin
supply groove 164.
[0042] Camshaft phaser attachment bolt 26 includes bolt supply
passages 188 extending radially outward from valve bore 154 to the
outer circumference of camshaft phaser attachment bolt 26 in order
to supply oil to linear valve spool lock pin supply groove 164 from
an oil source 190, which may be, by way of non-limiting example
only, an oil pump of internal combustion engine 10 which may also
provide lubrication to various elements of internal combustion
engine 10. The oil from oil source 190 is supplied to bolt supply
passages 188 through a camshaft supply passage 192 of camshaft 14
and an annular supply passage 194 formed radially between camshaft
phaser attachment bolt 26 and a camshaft counter bore 196 of
camshaft 14. Camshaft phaser attachment bolt 26 also includes a
bolt annular advance groove 198 that extends radially outward from
valve bore 154 such that bolt advance passages 200 extend from bolt
annular advance groove 198 to the outer circumference of camshaft
phaser attachment bolt 26 where bolt advance passages 200 provide
fluid communication from bolt annular advance groove 198 to rotary
valve body annular advance groove 108. Camshaft phaser attachment
bolt 26 also includes a bolt annular retard groove 202 that extends
radially outward from valve bore 154 such that bolt retard passages
204 extend from bolt annular retard groove 202 to the outer
circumference of camshaft phaser attachment bolt 26 where bolt
retard passages 204 provide fluid communication from bolt annular
retard groove 202 to rotary valve body annular retard groove 110.
Bolt annular advance groove 198 is spaced axially apart from bolt
annular retard groove 202 such that bolt annular retard groove 202
is closer to the bottom of valve bore 154 than bolt annular advance
groove 198. Camshaft phaser attachment bolt 26 also includes bolt
inner annular lock pin groove 206 which extends radially outward
form valve bore 154, a bolt outer annular lock pin groove 208 which
extends radially inward from the outer circumference of camshaft
phaser attachment bolt 26, and bolt lock pin passages 210 which
extend from bolt inner annular lock pin groove 206 to bolt outer
annular lock pin groove 208. Bolt inner annular lock pin groove 206
is spaced axially apart from bolt annular advance groove 198 such
that bolt annular advance groove 198 is axially between bolt inner
annular lock pin groove 206 and bolt annular retard groove 202.
Bolt outer annular lock pin groove 208 is aligned with rotary valve
spool lock pin passage 137 of rotary valve body 76. Camshaft phaser
attachment bolt 26 also includes bolt make-up oil passages 212
(only one bolt make-up oil passage 212 is shown in the figures)
therein which provide fluid communication from annular supply
passage 194 to a rotary valve body make-up groove 214 which extends
radially inward from rotary valve body through bore 86 of rotary
valve body 76 where a plurality of rotary valve body make-up
passages 216 provide fluid communication from rotary valve body
make-up groove 214 to rotary valve spool recirculation passages
122. A make-up check valve 218 is provided in each rotary valve
body make-up passage 216 in order to prevent oil from flowing from
rotary valve spool recirculation passages 122 to rotary valve body
make-up groove 214 while allowing oil to flow from rotary valve
body make-up groove 214 to rotary valve spool recirculation
passages 122.
[0043] Lock pin 31 selectively prevents relative rotation between
stator 18 and rotor 20 at a predetermined rotor position of rotor
20 within stator 18, which as shown, may be between a full advance
position, i.e. rotor 20 is rotated as far as possible within stator
18 in the advance direction of rotation, and a full retard
position, i.e. rotor 20 is rotated as far as possible within stator
18 in the retard direction of rotation. Lock pin 31 is slidably
disposed within a lock pin bore 220 formed in one vane 40 of rotor
20. Lock pin 31 and lock pin seat 62 are sized to substantially
prevent rotation between stator 18 and rotor 20 when lock pin 31 is
received within lock pin seat 62. When lock pin 31 is not desired
to be seated within lock pin seat 62, pressurized oil is supplied
to lock pin 31 through rotor lock pin passage 136 thereby urging
lock pin 31 out of lock pin seat 62 and compressing a lock pin
spring 222. Conversely, when lock pin 31 is desired to be seated
within lock pin seat 62, oil is vented from lock pin 31 through
rotor lock pin passage 136, thereby causing lock pin spring 222 to
urge lock pin 31 toward back cover 22 and lock pin 31 is seated
within lock pin seat 62 when rotor 20 is rotated to the
predetermined rotor position relative to stator 18. Supplying and
venting of pressurized oil to and from lock pin 31 is controlled by
linear valve spool 30 as will be described later in greater
detail.
[0044] As shown herein, biasing arrangement 32 includes advance
bias spring 148 and retard bias spring 152 which each take the form
of a clockspring where advance bias spring 148 applies a torque to
rotary valve spool 28 in the advance direction only when rotary
valve spool 28 is retarded relative to the predetermined rotary
valve spool position and where retard bias spring 152 applies a
torque to rotary valve spool 28 in the retard direction only when
rotary valve spool 28 is advanced relative to the predetermined
rotary valve spool position. Consequently, when rotary valve spool
28 is in the predetermined rotary valve position relative to stator
18, neither advance bias spring 148 nor retard bias spring 152
apply a torque to rotary valve spool 28. Alternatively, when rotary
valve spool 28 is in the predetermined rotary valve spool position,
advance bias spring 148 and retard bias spring 152 may apply
torques to rotary valve spool 28 that are equal in magnitude but
opposite in direction, thereby resulting in no net torque on rotary
valve spool 28. In order for advance bias spring 148 to operate
accordingly, advance bias spring 148 includes an outer advance bias
spring tang 224 at the radially outer end thereof and an inner
advance bias spring tang 226 at the radially inner end thereof.
Similarly, retard bias spring 152 includes an outer retard bias
spring tang 228 at the radially outer end thereof and an inner
retard bias spring tang 230 at the radially inner end thereof.
Outer advance bias spring tang 224 and outer retard bias spring
tang 228 are grounded to a bias spring cover 232 which is fixed to
front cover 24, and consequently advance bias spring 148 and retard
bias spring 152 are grounded to stator 18 by virtue of front cover
24 being attached to stator 18. Bias spring cover 232 is
substantially cup-shaped such that bias spring cover 232 includes a
bias spring sidewall 234 which is annular in shape and radially
surrounds advance bias spring 148 and retard bias spring 152, a
bias spring cover end wall 236 that is annular in shape and extends
radially inward from the end of bias spring sidewall 234 that is
distal from front cover 24, and a bias spring cover attachment
flange 238 that is annular in shape and extends radially outward
from the end of bias spring sidewall 234 that is proximal to front
cover 24. Bias spring cover end wall 236 defines a bias spring
cover aperture 240 extending axially therethrough which allows a
portion of actuator 156 to access linear valve spool 30. Bias
spring cover attachment flange 238 is used to fix bias spring cover
232 to front cover 24, by way of non-limiting example only, using
bias spring cover screws 242 which pass through bias spring cover
attachment flange 238 and threadably engage front cover 24. When
rotary valve spool 28 is retarded relative to the predetermined
rotary valve spool position, first bias spring extension end 146 of
bias spring extension 140 engages inner advance bias spring tang
226 of advance bias spring 148, thereby causing advance bias spring
148 to wind up and apply a torque to rotary valve spool 28 in the
advance direction of rotation. However, when rotary valve spool 28
is retarded relative to the predetermined rotary valve spool
position, inner retard bias spring tang 230 is disengaged from bias
spring extension 140, and consequently retard bias spring 152 does
not apply a torque to rotary valve spool 28. Conversely, when
rotary valve spool 28 is advanced of the predetermined rotary valve
spool position, second bias spring extension end 150 engages inner
retard bias spring tang 230, thereby causing retard bias spring 152
to wind up and apply a torque to rotary valve spool 28 in the
retard direction of rotation. However, when rotary valve spool 28
is advanced relative to the predetermined rotary valve spool
position, inner advance bias spring tang 226 is disengaged from
bias spring extension 140, and consequently advance bias spring 148
does not apply a torque to rotary valve spool 28. The function of
advance bias spring 148 and retard bias spring 152 will be
discussed in greater detail later.
[0045] Operation of camshaft phaser 12 will now be described with
continued reference to FIGS. 1-6. In order to rotate rotor 20 to a
desired rotational position relative to stator 18, rotary valve
spool 28 is rotated to a complementary desired rotational position
of rotary valve spool 28 relative to stator 18 which subsequently
causes rotor 20 to rotate to the desired rotational position
relative to stator 18 by either transferring oil from phasing
advance chambers 46 to phasing retard chambers 48 (advance timing)
or from phasing retard chambers 48 to phasing advance chambers 46
(retard timing). Furthermore, linear valve spool 30 is used to
rotate rotary valve spool 28 to the complementary desired
rotational position of rotary valve spool 28 relative to stator 18
by either supplying oil to rotary valve spool retard chambers 98
while venting oil from rotary valve spool advance chambers 96
(advance timing) or supplying oil to rotary valve spool advance
chambers 96 while venting oil from rotary valve spool retard
chambers 98 (retard timing).
[0046] When it is desired to position rotor 20 relative to stator
18 in the predetermined rotor position, no electric current is
applied to actuator 156, thereby allowing valve spring 158 to urge
linear valve spool 30 away from the bottom of valve bore 154 until
linear valve spool vent land 168 abuts a stop member 244 which may
be, by way of non-limiting example only, a snap ring within a snap
ring groove extending radially outward from valve bore 154. In this
way, valve spring 158 positions linear valve spool 30 in a linear
valve spool default position within valve bore 154 as shown in FIG.
6. In the linear valve spool default position, pressurized oil from
oil source 190 is supplied to linear valve spool supply groove 162
through camshaft supply passage 192, annular supply passage 194,
and bolt supply passages 188. Also in the linear valve spool
default position, linear valve spool supply groove 162 is placed in
fluid communication with rotary valve spool advance chambers 96 and
rotary valve spool retard chambers 98 simultaneously where fluid
communication between linear valve spool supply groove 162 and
rotary valve spool advance chambers 96 is provided through linear
valve spool axial supply passages 174, linear valve spool advance
supply passages 184, linear valve spool advance supply groove 165,
bolt annular advance groove 198, bolt advance passages 200, rotary
valve body annular advance groove 108, and rotary valve spool
advance passages 104 and where fluid communication between linear
valve spool supply groove 162 and rotary valve spool retard
chambers 98 is provided through bolt annular retard groove 202,
bolt retard passages 204, rotary valve body annular retard groove
110, and rotary valve spool retard passages 106. Consequently,
rotary valve spool advance chambers 96 and rotary valve spool
retard chambers 98 are in fluid communication with each other. As a
result, the torque provided by advance bias spring 148 or retard
bias spring 152 will rotate rotary valve spool 28 to the
predetermined rotary valve spool position which causes rotor 20 to
rotate to the predetermined rotor position due to oil flow as will
be described in greater detail later. More specifically, if rotor
20 is advanced of the predetermined rotor position, retard bias
spring 152 will rotate rotary valve spool 28 to the predetermined
rotary valve spool position. Conversely, if rotor 20 is retarded of
the predetermined rotor position, advance bias spring 148 will
rotate rotary valve spool 28 to the predetermined rotary valve
spool position. Also in the linear valve spool default position,
lock pin 31 is placed in fluid communication with linear valve
spool axial vent passage 172 as shown in FIGS. 3 and 6, thereby
allowing oil to drain from lock pin 31 and also allowing lock pin
spring 222 to urge lock pin 31 toward back cover 22 and into lock
pin seat 62 after rotor 20 has been rotated to the predetermined
rotor position as a result of rotary valve spool 28 being rotated
to the predetermined rotary valve spool position by advance bias
spring 148 or retard bias spring 152. Fluid communication from lock
pin 31 to linear valve spool axial vent passage 172 is provided
through rotor lock pin passage 136, annular rotary valve body lock
pin groove 134, rotary valve spool lock pin passage 137, bolt outer
annular lock pin groove 208, bolt lock pin passages 210, bolt inner
annular lock pin groove 206, and second linear valve spool radial
vent passage 180, thereby allowing oil to drain out of valve bore
154 and back to oil source 190.
[0047] Reference will continue to be made to FIGS. 1-5 and
additional reference will now be made to FIGS. 7A-7E. When it is
desired to retard the rotational position of rotor 20 relative to
stator 18, an electric current of a first magnitude is applied to
actuator 156, thereby causing actuator 156 to urge linear valve
spool 30 toward the bottom of valve bore 154 slightly, thereby
compressing valve spring 158 slightly. In this way, actuator 156
positions linear valve spool 30 in a linear valve spool retard
position within valve bore 154 as shown in FIG. 7A. In the linear
valve spool retard position, rotary valve spool retard chambers 98
are placed in fluid communication with linear valve spool axial
vent passage 172 while rotary valve spool advance chambers 96 are
placed in fluid communication with linear valve spool supply groove
162, thereby causing oil to flow out of rotary valve spool retard
chambers 98 while allowing oil to flow into rotary valve spool
advance chambers 96 from oil source 190 and also causing rotary
valve spool 28 to rotate in the retard direction of rotation as
shown in FIGS. 7B and 7C. More specifically, rotary valve spool
retard chambers 98 are placed in fluid communication with linear
valve spool axial vent passage 172 through rotary valve spool
retard passages 106, rotary valve body annular retard groove 110,
bolt retard passages 204, bolt annular retard groove 202, and first
linear valve spool radial vent passage 178 while rotary valve spool
advance chambers 96 are placed in fluid communication with linear
valve spool supply groove 162 through linear valve spool axial
supply passages 174, linear valve spool advance supply passage 184,
linear valve spool advance supply groove 165, bolt annular advance
groove 198, bolt advance passages 200, rotary valve body annular
advance groove 108, and rotary valve spool advance passages 104.
Also in the linear valve spool retard position, lock pin 31 is
placed in fluid communication with linear valve spool supply groove
162, thereby causing pressurized oil to be supplied to lock pin 31
from oil source 190 and also causing lock pin 31 to retract from
lock pin seat 62. More specifically, lock pin 31 is placed in fluid
communication with linear valve spool supply groove 162 through
linear valve spool axial supply passages 174, linear valve spool
lock pin supply passage 186, linear valve spool lock pin supply
groove 164, bolt inner annular lock pin groove 206, bolt lock pin
passages 210, bolt outer annular lock pin groove 208, rotary valve
spool lock pin passage 137, annular rotary valve body lock pin
groove 134, and rotor lock pin passage 136. When rotary valve spool
28 is rotated in the retard direction relative to stator 18, rotary
valve spool lands 116 are moved out of alignment with rotor advance
passages 70 and rotor retard passages 72, thereby providing fluid
communication between supply chambers 112 and phasing advance
chambers 46 and also between vent chambers 114 and phasing retard
chambers 48. Consequently, torque reversals of camshaft 14 which
tend to pressurize oil within phasing retard chambers 48 cause oil
to be communicated from phasing retard chambers 48 to phasing
advance chambers 46 via rotor retard passages 72, vent chambers
114, rotary valve spool recirculation passages 122, annular rotary
valve spool recirculation groove 118, recirculation recesses 120,
supply chambers 112, and rotor advance passages 70. However, torque
reversals of camshaft 14 which tend to pressurize oil within
phasing advance chambers 46 and apply a torque to rotor 20 in the
advance direction are prevented from venting oil from phasing
advance chambers 46 because recirculation check valves 74 prevent
oil from flowing from phasing advance chambers 46 to phasing retard
chambers 48. Oil continues to be supplied to phasing advance
chambers 46 from phasing retard chambers 48 until rotor 20 is
rotationally displaced sufficiently far for each rotary valve spool
land 116 to again align with respective rotor advance passages 70
and rotor retard passages 72 as shown in FIG. 7D, thereby again
preventing fluid communication into and out of phasing advance
chambers 46 and phasing retard chambers 48 and hydraulically
locking the rotational position of rotor 20 relative to stator 18.
In FIG. 7E, which is the same cross-sectional view as FIG. 7C, the
reference numbers have been removed for clarity, and arrows R have
been included to represent oil that is being recirculated for
rotating rotor 20 relative to stator 18. It should be noted that
arrow R in FIG. 7E is shown in dotted lines where the flow is in a
different plane than FIG. 7E and more particularly, where the flow
is through annular rotary valve spool recirculation groove 118 and
rotary valve spool recirculation passages 122. It should be noted
that the flow of oil from phasing retard chambers 48 to phasing
advance chambers 46 as described relative to the linear valve spool
retard position is the same as when retard bias spring 152 is used
to rotate rotary valve spool 28 to the predetermined rotary valve
spool position when linear valve spool 30 is in the linear valve
spool default position.
[0048] Reference will continue to be made to FIGS. 1-5 and
additional reference will now be made to FIG. 8. When no change in
phase relationship between camshaft 14 and the crankshaft of
internal combustion engine 10 is desired, an electric current of a
second magnitude is applied to actuator 156, thereby causing
actuator 156 to urge linear valve spool 30 toward the bottom of
valve bore 154 slightly more than in the retard linear valve spool
position, thereby compressing valve spring 158 slightly more than
in the linear valve spool retard position. In this way, actuator
156 positions linear valve spool 30 in a linear valve spool hold
position within valve bore 154 as shown in FIG. 8. In the linear
valve spool hold position, fluid communication into and out of
rotary valve spool advance chambers 96 and rotary valve spool
retard chambers 98 is blocked by linear valve spool retard land 169
and linear valve spool advance land 170 respectively, thereby
hydraulically locking rotary valve spool 28 and preventing relative
rotation between rotary valve spool 28 and between rotor 20 and
stator 18. Also in the linear valve spool hold position, lock pin
31 is placed in fluid communication with linear valve spool supply
groove 162, thereby causing pressurized oil to be supplied to lock
pin 31 from oil source 190 and also causing lock pin 31 to retract
from lock pin seat 62. More specifically, lock pin 31 is placed in
fluid communication with linear valve spool supply groove 162
through linear valve spool axial supply passages 174, linear valve
spool lock pin supply passage 186, linear valve spool lock pin
supply groove 164, bolt inner annular lock pin groove 206, bolt
lock pin passages 210, bolt outer annular lock pin groove 208,
rotary valve spool lock pin passage 137, annular rotary valve body
lock pin groove 134, and rotor lock pin passage 136.
[0049] Reference will continue to be made to FIGS. 1-5 and
additional reference will now be made to FIGS. 9A-9E. When it is
desired to advance the rotational position of rotor 20 relative to
stator 18, an electric current of a third magnitude is applied to
actuator 156, thereby causing actuator 156 to urge linear valve
spool 30 toward the bottom of valve bore 154 slightly more than in
the linear valve spool hold position, thereby compressing valve
spring 158 slightly more than in the linear valve spool hold
position. In this way, actuator 156 positions linear valve spool 30
in a linear valve spool advance position within valve bore 154 as
shown in FIG. 9A. In the linear valve spool advance position,
rotary valve spool advance chambers 96 are placed in fluid
communication with linear valve spool axial vent passage 172 while
rotary valve spool retard chambers 98 are placed in fluid
communication with linear valve spool supply groove 162, thereby
causing oil to flow out of rotary valve spool advance chambers 96
while allowing oil to flow into rotary valve spool retard chambers
98 from oil source 190 and also causing rotary valve spool 28 to
rotate in the advance direction of rotation as shown in FIGS. 9B
and 9C. More specifically, rotary valve spool advance chambers 96
are placed in fluid communication with linear valve spool axial
vent passage 172 through rotary valve spool advance passages 104,
rotary valve body annular advance groove 108, bolt advance passages
200, bolt annular advance groove 198, and second linear valve spool
radial vent passage 180 while rotary valve spool retard chambers 98
are placed in fluid communication with linear valve spool supply
groove 162 through linear valve spool axial supply passages 174,
linear valve spool retard supply passages 182, bolt annular retard
groove 202, bolt retard passages 204, rotary valve body annular
retard groove 110, and rotary valve spool retard passages 106. Also
in the linear valve spool advance position, lock pin 31 is placed
in fluid communication with linear valve spool supply groove 162,
thereby causing pressurized oil to be supplied to lock pin 31 from
oil source 190 and also causing lock pin 31 to retract from lock
pin seat 62. More specifically, lock pin 31 is placed in fluid
communication with linear valve spool supply groove 162 through
linear valve spool axial supply passages 174, linear valve spool
lock pin supply passage 186, linear valve spool lock pin supply
groove 164, bolt inner annular lock pin groove 206, bolt lock pin
passages 210, bolt outer annular lock pin groove 208, rotary valve
spool lock pin passage 137, annular rotary valve body lock pin
groove 134, and rotor lock pin passage 136. When rotary valve spool
28 is rotated in the advance direction relative to stator 18,
rotary valve spool lands 116 are moved out of alignment with rotor
advance passages 70 and rotor retard passages 72, thereby providing
fluid communication between supply chambers 112 and phasing retard
chambers 48 and also between vent chambers 114 and phasing advance
chambers 46. Consequently, torque reversals of camshaft 14 which
tend to pressurize oil within phasing advance chambers 46 cause oil
to be communicated from phasing advance chambers 46 to phasing
retard chambers 48 via rotor advance passages 70, vent chambers
114, rotary valve spool recirculation passages 122, annular rotary
valve spool recirculation groove 118, recirculation recesses 120,
supply chambers 112, and rotor retard passages 72. However, torque
reversals of camshaft 14 which tend to pressurize oil within
phasing retard chambers 48 and apply a torque to rotor 20 in the
retard direction are prevented from venting oil from phasing retard
chambers 48 because recirculation check valves 74 prevent oil from
flowing from phasing retard chambers 48 to phasing advance chambers
46. Oil continues to be supplied to phasing retard chambers 48 from
phasing advance chambers 46 until rotor 20 is rotationally
displaced sufficiently far for each rotary valve spool land 116 to
again align with respective rotor advance passages 70 and rotor
retard passages 72 as shown in FIG. 9D, thereby again preventing
fluid communication into and out of phasing advance chambers 46 and
phasing retard chambers 48 and hydraulically locking the rotational
position of rotor 20 relative to stator 18. In FIG. 9E, which is
the same cross-sectional view as FIG. 9C, the reference numbers
have been removed for clarity, and arrows R have been included to
represent oil that is being recirculated for rotating rotor 20
relative to stator 18. It should be noted that arrow R in FIG. 9E
is shown in dotted lines where the flow is in a different plane
than FIG. 7E and more particularly, where the flow is through
annular rotary valve spool recirculation groove 118 and rotary
valve spool recirculation passages 122. It should be noted that the
flow of oil from phasing advance chambers 46 to phasing retard
chambers 48 as described relative to the linear valve spool advance
position is the same as when advance bias spring 148 is used to
rotate rotary valve spool 28 to the predetermined rotary valve
spool position when linear valve spool 30 is in the default linear
valve spool position.
[0050] It should be noted that oil that may leak from phasing
advance chambers 46, phasing retard chambers 48, or passages and
interfaces associated therewith is replenished from oil provided by
oil source 190. Replenishing oil is accomplished by oil source 190
supplying oil to annular rotary valve spool recirculation groove
118 via camshaft supply passage 192, annular supply passage 194,
bolt make-up oil passages 212, rotary valve body make-up groove
214, rotary valve body make-up passages 216, make-up check valve
218, and rotary valve spool recirculation passages 122. From
annular rotary valve spool recirculation groove 118, the oil may be
supplied to phasing advance chambers 46 or phasing retard chambers
48 as necessary by one or more of the processes described
previously for advancing or retarding rotor 20.
[0051] It is important to note that oil exclusively flows from
supply chambers 112 to whichever of phasing advance chambers 46 and
phasing retard chambers 48 need to increase in volume in order to
achieve the desired phase relationship of rotor 20 relative to
stator 18 while oil exclusively flows to vent chambers 114 from
whichever of phasing advance chambers 46 and phasing retard
chambers 48 need to decrease in volume in order to achieve the
desired phase relationship of rotor 20 relative to stator 18. In
this way, only one set of recirculation check valves 74 are needed
acting in one direction within rotary valve spool 28 in order to
achieve the desired phase relationship of rotor 20 relative to
stator 18. Consequently, it is not necessary to switch between sets
of check valves operating in opposite flow directions or switch
between an advancing circuit and a retarding circuit. In the case
of rotary valve spool 28 described herein, a unidirectional flow
circuit is defined within rotary valve spool 28 when rotary valve
spool 28 is moved to a position within rotor 20 to allow either
flow from phasing advance chambers 46 to phasing retard chambers 48
or from phasing retard chambers 48 to phasing advance chambers 46
where the flow circuit prevents flow in the opposite directions.
Consequently, the flow circuit is defined by rotary valve spool 28
which is simple in construction and low cost to produce.
[0052] While clockwise rotation of rotor 20 relative to stator 18
has been described as advancing camshaft 14 and counterclockwise
rotation of rotor 20 relative to stator 18 has been described as
retarding camshaft 14, it should now be understood that this
relationship may be reversed depending on whether camshaft phaser
12 is mounted to the front of internal combustion engine 10 (shown
in the figures) or to the rear of internal combustion engine
10.
[0053] While recirculation check valves 74 have been illustrated as
reed valves, it should now be understood that recirculation check
valves 74 can take other forms commonly know, by way of
non-limiting example only, a ball biased by a coil spring.
Furthermore, recirculation check valves 74 can be placed in
locations other than embodied herein. Also furthermore, a single
recirculation check valve 74 may be used when all supply chambers
112 or all vent chambers 114 are in communication with a common
passage.
[0054] Using oil supplied to and vented from rotary valve spool
advance chambers 96 and rotary valve spool retard chambers 98 to
rotate rotary valve spool 28 allows for many monitored parameters
of internal combustion engine 10 to be used for determining the
desired phase relationship because the many monitor parameters can
be processed and used to command linear valve spool 30 which
controls the supply and venting of oil to and from rotary valve
spool advance chambers 96 and rotary valve spool retard chambers 98
to rotate rotary valve spool 28. Using oil supplied to and vented
from rotary valve spool advance chambers 96 and rotary valve spool
retard chambers 98 to rotate rotary valve spool 28 also allows
implementation of biasing arrangement 32 to rotate rotary valve
spool 28 to a position that will allow rotor 20 to rotate to a
predetermined rotor position within stator 18. Since biasing
arrangement 32 only needs to rotate rotary valve spool 28, rather
than rotor 20 directly, advance bias spring 148 and retard bias
spring 152 can have low spring rates compared to bias springs
typically implemented in camshaft phasers which must rotate the
rotor directly. This arrangement provides a means for rotor 20 to
move to the predetermined rotor position relative to stator 18
whenever actuator 156 is not energized and enables lock pin 31 to
engage lock pin seat 62 at the predetermined rotor position.
[0055] While rotary valve spool vanes 80 have been illustrated and
described herein as being grounded to rotor 20, it should now be
understood that rotary valve spool 28 may be reconfigured so as to
ground rotary valve spool vanes 80 to front cover 24 or some other
component that rotates together with stator 18, thereby grounding
rotary valve spool vanes 80 in effect to stator 18. When rotary
valve spool vanes 80 are grounded in effect to stator 18, rotary
valve spool 28 permits self-correction of drift of rotor 20 as
disclosed in U.S. patent application Ser. No. 14/554,385 to
Haltiner and in U.S. patent application Ser. No. 14/554,400 to
Haltiner et al., the disclosures of which are incorporated herein
by reference in their entirety. It should be noted that biasing
arrangement 32 does in effect position rotary valve spool 28
relative to stator 18 so that the position of rotor 20 is
self-correcting when actuator 156 is not energized.
[0056] While this invention has been described in terms of
preferred embodiments thereof, it is not intended to be so limited,
but rather only to the extent set forth in the claims that
follow.
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